(1) Field of the Invention
The present invention relates generally to apparatus for rapid oxidation of liquid feed stock to produce gas, and more particularly to an improved liquid gasification reactor with a pressurized chamber and operating environment.
(2) Background Information
The inventors herein have disclosed a liquid gasification process and apparatus which utilizes rapid oxidation of a water based solution to produce a gas substantially composed of hydrogen and carbon monoxide (COH2). The COH2 is a gas which will burn very cleanly in oxygen or air, and therefore is desirable for use as a fuel for internal combustion engines and the like. When combusted, COH2 produces carbon dioxide and water vapor, thereby adding very little, if any, pollution to the environment.
Storage of COH2 gas can be a problem, and it is therefore desirable to produce COH2 gas on an on-demand basis. U.S. Pat. No. 5,159,900 discloses the use of an electrical arc between two carbon electrodes submersed in water to produce the reaction necessary to rapidly oxidize carbon and produce COH2 gas. Because the carbon electrodes were consumed during the reaction, there was no residue. While water can be easily added within the reaction chamber without disrupting the reaction, the carbon electrodes cannot be replaced in this reaction chamber without disrupting, the reaction. For this reason, the inventors herein developed a process and apparatus which continuously replenish the carbon electrodes from a biomass feedstock by alternately electroplating the electrodes.
U.S. Pat. No. 5,417,817 describes a sensor which detects the position of the it electrical arc within the reaction chamber and switches the polarity of the current to alternate the plating on the electrodes, thereby maintaining the point of reaction near the center of the chamber. U.S. Pat. No. 6,183,608 discloses an electrode positioning mechanism that senses the physical electrode contact pressure to protect the carbon deposit on the electrode from excessive contact pressure when the arc is initially struck and during operation of the apparatus.
Improvements to the efficiency of the reaction chamber were accomplished in U.S. Pat. No. 6,113,865, wherein light energy of the electric arc is reflected and focused into the point of reaction using a highly reflective spherical reaction chamber. When focused back to the point of reaction, light energy is converted to heat and added to the heat of the reaction. Because this process is an endothermic reaction, the recovered light energy, as heat, will increase the rate of reaction and improve the efficiency of gas production.
Observations during ongoing development of the rapid oxidation process have provided information relative to the pressure generated by the electro-thermochemical reaction (electrochemical). As pressure increased, the reaction kinetics (rate or speed) also increased, resulting in a greater volume of gas being produced within a predetermined time, but without increasing the electrical energy input. These observations are fully in accord with the Le Chxc3xa2telier principle. As noted in U.S. Pat. No. 6,113,865, it is desirable to increase pressure at the reaction point in order to increase the efficiency of the reaction.
While an increase in pressure will clearly increase efficiency of the reactor, the practical aspects of providing this increased pressure within the reaction chamber have thus far not been overcome. Because the positioning mechanism of the electrodes is sensitive to physical contact pressure, a higher chamber pressure will cause the pressure differential between the inside of the reaction chamber and the outside (ambient) environment to increase to a value which causes the positioning mechanism to erroneously reverse. Thus, the positioning mechanism would have difficulty in distinguishing between contact pressure of the electrode and the pressure differential between the interior of the chamber and the exterior.
Other practical problems encountered with increasing the pressure within the reaction chamber include the necessity of using tight fitting seals for the movable electrode holders. This also would negate the sensitivity of the electrode physical contact sensing feature of the positioning mechanism, and would also require a more powerful drive system to overcome the drag caused by the tighter seals.
It is therefore a general object of the present invention to provide an improved reactor configuration for a liquid gasification process which enhances the efficiency of the electro-thermochemical reaction by increasing pressure within the reaction chamber.
Another object of the invention is to provide an improved reactor that includes an electrode positioning mechanism and sensors for detecting physical contact pressure of the electrodes, while operating within a pressurized reaction chamber.
These and other objects will be apparent to those skilled in the art.
The reactor of the present invention includes a housing with an input port for liquid feedstock and an exhaust port for gas produced by a liquid gasification process. The housing includes a pressurized reaction chamber with a pair of spaced apart electrodes having inward free ends immersed in the liquid feedstock. One of the electrodes is mounted on an operable shaft, to move inward and outward relative to the other electrode. A drive mechanism for the operable shaft is located outside the reaction chamber to selectively move the shaft. The reaction chamber is pressurized to increase efficiency of the reactor, and the chamber within which the drive mechanism is located is pressurized to substantially the same pressure as the reaction chamber.